You'll be amazed at the daily going-ons you learn through following people. Especially on Twitter. I've seen tweets that tell me about layoffs, job openings and job changes (which means their old job is open). The secret is to follow people who work there rather than the company itself. You'll get the real story that way.

Armed with that information, you can "luck in" to calling the hiring person just as they need someone. Amazing how timing can change their reaction to your call.